Carburetor mounting

ABSTRACT

A mounting assembly for a carburettor, the assembly including a seal made of heat insulating material housed in an opening in an engine block or manifold and sealing against the outside of a delivery tube from the carburettor.

United States Patent Notaras et al.

[ Jan. 1,1974

[ CARBURETOR MOUNTING [76] Inventors: John Arthur Notaras; Angelo Lambrinos Notaras, both of 15-21 Reynolds St., Balmain, New South Wales, Australia [22] Filed: Aug. 7, 1972 [21] Appl. No.: 278,384

[52] US. Cl. 123/52 M, 261/65 [51] Int. Cl. F02b 77/00, F02b 77/12 [58] Field of Search 123/52 M, 52 MV,

[56] References Cited UNITED STATES PATENTS 2,896,597 7/1959 Patrick 123/52 MV 3,114,669 12/1963 Herbst 123/52 M 3,671,208 6/1972 Medsker v 261/65 3,376,890 4/1968 Hanson et al 261/65 Primary Examiner-Laurence M. Goodridge Assistant Examiner-Dennis Toth Att0rneyEmory L. Groff et al.

[57] ABSTRACT 5 Claims, 2 Drawing Figures CARBURETOR MOUNTING This invention relates to improvements in the means of mounting of carburettors on engines.

It has long been a problem to mount a carburettor on an engine so that there are no air leaks at the joint therebetween and so that the heat transference between the engine and the carburettor is kept to a level where the temperature of the carburettor never reaches the temperature where heat vaporisation of the liquid fuel therein occurs. The latter problem is of particular importance on small fast revving engines such as those used on chain saws and lawn mowers. The prob lem is accentuated in the latter cases where the carburettor is directly mounted over the cylinder inlet.

In the past it has been common to clamp a flange on the carburettor to a surface of the engine, or a flange of an inlet manifold, with a thick spacer of insulation material therebetween to limit heat transfer. Some common insulating materials are particularly successful in this regard but are unstable requiring frequent tightening of the clamping bolts or nuts mounting the carburettor on the engine, inorder to maintain the joint air tight. Fatigue cracks and/or distortion can also occur in the insulation, due for example to engine vibration, with resultant air leakage.

The present invention provides a mounting arrangement for carburettors which maintains a good seal be tween the carburettor and the engine and a high degree of heat insulation therebetween.

Accordingly the present invention provides a mounting assembly for a carburettor, said mounting means comprising a seal member made of heat insulating material and having an opening therethrough defined by a sealing lip, said seal member being adapted to be mounted over the fuel inlet port of an engine or an inlet manifold therefore to seal said port except for said opening and a mounting tube made of heat insulating material and adapted to be coupled to or forming part of a carburettor and to sealingly engage said sealing lip.

Two forms of the invention are described with reference to the accompanying drawings in which:

FIG. 1 is a fragmentary cross-sectional elevation of one form of the invention, and

FIG. 2 is a cross-sectional elevation of an alternative form of seal member.

Referring to FIG. 1 the manifold or engine is indicated 1 and has a port 2. The port is recessed at its outer edge at 3 and a seal member 4 is mounted therein. The seal comprises an outer or body part 5 of ring shape adapted to be tight fit in the recess 3. The body part 5 is connected to an inner or central ring part 6 on which there is a lip 7. The inner and outer parts are connected by an annular flexible portion 8 which allows lateral movement of the lip 7 relative to the body 5 to accommodate any misalignments between the axes of the recess 3 and the carburettor mounting tube 9. Such misalignment may arise from initial assembly or from vibration during operation of the engine. Preferably the whole seal member is moulded from rubber or plastic or suitable elastomeric material and as will be seen in the drawing the seal member has a cross sectional configuration resembling an M. The lip 7 is on the outer surface of one outer leg of the M" which constitutes the inner part of the seal member and the other outer leg of the M constitutes the outer part of the seal member. A circular resilient spring (preferably of endless coil type) holds the lip in a con tracted position.

An annulus 11 is fixed to the seal member outer part and bridges the two peaks at the top of the M. The annulus provides a retaining member for the inner part 6 so that on withdrawal of the tube 9 the lip 7 will not fold back and allow the spring 10 to become displaced. The annulus 11 is preferably made of heat insulating material and may be fixed to the seal member in any suitable way e.g. by glue.

It is obvious however that the annulus 11 may be of any suitable alternative shape and may be held in the recess 3 by clamp means rather than being fixed to the seal member. 7

Referring to FIG. 2 the manifold or engine is indicated 1' and has a port 12. The port is recessed at its outer edge at 13 and a seal 14 is mounted therein. The seal as illustrated has a body part 15 which neatly fits the recess 13 and a sealing lip 16 which is maintained circular and in engagement with the mounting tube by anendless spring coil 17. The mounting tube 18 (preferably of heat insulating material) has a body-part which is a tight fit in the lip 16. The mounting tube 18 also has a flange 19 at its upper end to which can be fitted a carburettor shown in dotted outline at 20.

Any suitable means can be used to brace the mounting tube 18, in the illustrated case a bracket 21 (which may be made of insulating material) is provided. The bracket is secured at one end, for example, to a coller part of the engine, not shown, and has a hole 23 whereby it can be bolted to the carburettor. The flange 19 has holes 24 whereby the carburettor 20 is mountable on the mounting tube 18. Alternatively, the tube 18 can be part of or be secured to carburettor by any other suitable means.

It will be seen from the illustrations that no tightening of the seal between the carburettor or its mounting tube and the engine is necessary after initial fitting and an effective seal is maintained at all times.

It will be understood that seals other than those illustrated may be used, an example of such a seal would be an O ring.

We claim:

1. An assembly for mounting a carburetor on an internal combustion engine, said engine having an opening communicating with the engine combustion chamber to admit a fuel-air mixture from the carburetor to the engine, said assembly comprising a ring-like seal of heat insulating material secured on said engine to encircle said opening, a resilient sealing lip on the seal defining the periphery of a central opening through the seal and a carburetor mounting tube passing through said seal and exteriorly sealingly engaged by said lip.

2. An assembly as claimed in claim 1, including a resilient member which urges said sealing lip into a sealing engagement with the carburetor mounting tube.

3. An assembly as claimed in claim 2, wherein the resilient member is an endless coil spring.

4. An assembly as claimed in claim 2, wherein said seal includes an outer part, an inner part including said lip and a continuous flexible portion connecting the inner and outer parts, said flexible portion permitting lateral relative movement of the inner and outer parts to accommodate any misalignment of the mounting tube and said engine opening and a retaining member to prevent the inner part of the seal from moving axially relative to the outer part of the seal during disengagement and the mounting tube from the lip.

5. An assembly, as claimed in claim 4, wherein the seal member is circular in shape and of generally M configuration in cross-section. 

1. An assembly for mounting a carburetor on an internal combustion engine, said engine having an opening communicating with the engine combustion chamber to admit a fuel-air mixture from the carburetor to the engine, said assembly comprising a ring-like seal of heat insulating material secured on said engine to encircle said opening, a resilient sealing lip on the seal defining the periphery of a central opening through the seal and a carburetor mounting tube passing through said seal and exteriorly sealingly engaged by said lip.
 2. An assembly as claimed in claim 1, including a resilient member which urges said sealing lip into a sealing engagement with the carburetor mounting tube.
 3. An assembly as claimed in claim 2, wherein the resilient member is an endless coil spring.
 4. An assembly as claimed in claim 2, wherein said seal includes an outer part, an inner part including said lip and a continuous flexible portion connecting the inner and outer parts, said flexible portion permitting lateral relative movement of the inner and outer parts to accommodate any misalignment of the mounting tube and said engine opening and a retaining member to prevent the inner part of the seal from moving axially relative to the outer part of the seal during disengagement and the mounting tube from the lip.
 5. An assembly, as claimed in claim 4, wherein the seal member is circular in shape and of generally ''''M'''' configuration in cross-section. 